Passing Data between two open forms - vb.net

Question

I know this has been answered many times over and I am actually using code that seems to be working but I can't seem to get the actually data to be presented in the receiving form.
In the sending form I am select an item in a tree menu which triggers an event to open the receiving form and then pass the data. I put a break point in my receiving code and can see the data is applied to the variable. I applied that variable to text box but it does not appear on the open form.
Here is the code from the sending form. I am first checking to see if the form is open. My variable that I am passing is a string strControl.
If Application.OpenForms.OfType(Of Guidance_Info).Any() Then
Dim f1 As New Guidance_Info()
Guidance_Info.LoadGuidance_Info(strControl)
Else
Dim f1 As New Guidance_Info()
Guidance_Info.LoadGuidance_Info(strControl)
f1.Show()
End If
Here is the code from the receiving form. I first apply the variable to the table adapter, then a text box and then a message box. The only item that presents the data is the message box. Using a breakpoint I can see that the variable is being passed to the both the text box and the table adapter.
Friend Sub LoadGuidance_Info(ByVal ControlID As String)
Me._800_53_CtrlTableAdapter.FillByControl(Me.AssessGuidanceDataSet1._800_53_Ctrl,
ControlID)
Me.lblControl.Text = ControlID
MsgBox(ControlID)
End Sub
As you can see from this image the variable is receive properly:
Friend sub LoadGuidance_Info
I also tried using f1.ShowDialog() instead of f1.Show() but got the same results. The problem with the Dialog, you can't use the sending form until you close the receiving form.
Any help would be appreciated:

Answer 1

Your problem has nothing to do with passing data, but what you are passing it to.
You look for an open form instance but whether you find one or not, you create a New form instance, pass the data to a default form instance, then show the (New) form instance you created. In the end you have as many as 3 instances of the same form:
' first instance may be in the collection
If Application.OpenForms.OfType(Of Guidance_Info).Any() Then
...similar issue to below
Else
' create a NEW instance (#2)
Dim f1 As New Guidance_Info()
' use/create a default instance
Guidance_Info.LoadGuidance_Info(strControl)
' show #2
f1.Show()
End If
Neither #2 nor #3 can ever be the one that may be showing. Rather than just checking the collection for an instance, get it and check that (using more idiomatic naming):
Dim f1 = Application.OpenForms.OfType(Of GuidanceInfo)().FirstOrDefault
If f1 IsNot Nothing Then
' use existing
f1.LoadInfo(strControl)
Else
' create, update, show one new form instance
f1 = New GuidanceInfo()
f1.LoadInfo(strControl)
f1.Show()
End If